The present disclosure relates to punching apparatuses, post-processing apparatuses, and image forming apparatuses.
To date, punching apparatuses, for post-processing apparatuses, which perform punching process at predetermined positions in paper sheets (mediums on which image formation is performed) discharged from image forming apparatus bodies, have been known. The punching apparatus includes a punching blade (hole-punching blade), a paper sheet width direction movement portion (orthogonal direction movement portion), a cylindrical member (rotation member), and punching-completion detection means. The paper sheet width direction movement portion moves the punching blade in a paper sheet width direction orthogonal to a paper sheet conveying direction. In the cylindrical member, the punching blade is disposed so as to project from the circumferential surface, and the cylindrical member rotates. The punching-completion detection means detects for completion of the punching process by the punching blade.
In the conventional punching apparatus, in a case where the punching-completion detection means detects completion of the punching process, the paper sheet width direction movement portion moves the punching blade in the paper sheet width direction. Thus, the conventional punching apparatus enables efficient execution of the punching process, and reduction of time for the punching process.
In the conventional punching apparatus, even when rotation of the cylindrical member is to be stopped so as to stop the punching blade at a punching reference position after the completion of the punching process, the cylindrical member may rotate due to inertia. Thus, the punching blade may move beyond the punching reference position toward a through hole punching position. When the punching blade moves beyond the punching reference position toward the through hole punching position, the punching blade may stop with the punching blade penetrating the paper sheet. If the punching blade is moved in the paper sheet width direction with the punching blade penetrating the paper sheet, the paper sheet may be damaged by the punching blade.